I'm 45, and my last two boyfriends were both 18 years younger than me. The oldest person I've dated was something like 2 or 3 years older than me (it didn't last long, and although we're still friendly when we see each other, it's been at least a year, maybe two, since I last saw him). As has been noted above, I was the one who was the more concerned about the age difference in each case with my younger boyfriends (though my last bf did ask me not to volunteer my age when I was meeting his parents for the first time - I think he thought they would find it weird).
The thing for me is that I don't think of myself as 45. I'm not immature - I've held a series of jobs (both paid and volunteer) with a fair amount of responsibility, I've been married (my ex-husband is two years younger than me), and I own my home. (Well, the bank still owns about half of it.
) I don't know if it's because I've always been told that I look younger than my age, or because I have a number of friends who are between 10 and 25 years younger than me, or what. (In fact, my last bf told me that he had no idea how old I was when we first met.) But mentally, I feel like I'm around 30. As a result, I'm not much interested in most guys around my age, and I'm certainly not interested in men who are older than me. I find them dull, for the most part, though there are a few exceptions - mostly people I know through fandom, which is probably because they also tend to be mentally younger than their years (yet not immature).
Does that make sense? I'm not even certain that I'm not just trying to justify liking younger men.
Of course, it's all kind of irrelevant because I haven't even had a date since my last bf and I broke up, three years ago.